In many separators known in the art, gravel or the like is laid across a vibrating shaker screen. The screen has a mesh size suitable for passing particles of a predetermined size therethrough while supporting and carrying larger particles to a chute, conveyor or the like. As a rule of thumb, it is generally stated that the downwardly sloping length of the shaker screen should be about two and a half times the width of the screen in order to maximize the separating rate and the quality of separation while keeping the separator to a reasonable size. Such separators generally require hoppers at the input end of the shaker screen to funnel the particles onto the screen.
Rich soil, or loam, is presently in high demand. Due to many regional restrictions on excavating, however, those who supply loam must often go to remote locations that offer rough top soil and separate the loam from coarse material such as gravel, decaying roots, stumps and so on. In order to avoid having to transport both the loam and the coarse material, it is highly desirable that a portable apparatus be used for separating the loam from the coarse material. To this end, many past shaker screen separators mounted on a truck or trailer have been reduced-scale imitations of stationary separator plants. Because of the extended lengths and reduced widths of these shaker screen separators, the separators require infeed hoppers or conveyors. These separators have not been reliable in separating loam from extremely bulky material, such as root stumps and the like, which have clogged the hoppers or conveyors.
An object of the present invention is to provide a shaker screen separator for separating loam or other fine material from exceptionally coarse material, that separator being portable for easy transport to the most remote regions.
A further object of this invention is to provide such a separator which is of exceptionally simple construction, not requiring the use of infeed hoppers, chutes or conveyors, but which provides an outfeed conveyor for the fine material.
Yet another object of this invention is to provide such a separator which is exceptionally durable even when used to separate the loam from heavy and bulky material such as tree stumps and large rocks.